Refrigeration



May 7, 1929- B. c. VON PLATEN ET AL REFRIGERAT I ON Filed June 5, 1927 5 Sheets-Sheet l Ms #www #/WATTORNEY May 7, 1929- B. c. voN PLATEN ET AL 1,711,553

REFRIGEPATI ON Filed June 5, 1927 3 Sheets-Sheet 2 May 7, 1929- B. c. VON PLATEN ET AL REFRIGERATI ON Filed June 5, 1927 5 sheen-sheet 5 Patented lMay 7, 1929. 4

UNITED STATES PATENT. OFFICE BALTZAR CARL von PLATEN, CARL GEORG MUNTE'RS, AND siGUnD MATTIAS BCK- STRM, OF STOCKHOLM, SWEDEN, ASSIGNORS T ELECTROLUX-SERVEL ('.iORPOIRAA TION, OF NEW YORK, N. Y A CORPORATION OF DELAWARE.

REFRIGERATION.

`Application led .Tune 3, A1927, Serial' No. 196,179, and in S'weden .Tune a, 1926.

Our inventionrelates to the art of refrigeration and relates particularly to that type of absorption refrigerating system wherein a constant total pressure is maintained throughout. It is the purpose of our inven-k tion to distribute refrigerative duty between several evaporators. 'In the preferred form, evaporation of the cooling agent (otherwise called refrigerant) takes place in an auxiliary agent, such as hydrogen gas. In accordance with a preferred forni of the invention, inoretlian sufficient cooling agent is supplied `to one evaporator and the excess is evaporated in a secondary evaporator. The secondary evaporation may be used for cooling fluid within the system or for cooling substances outside the system. By our invention a complete evaporation of cooling agent is obtained and the refrigerative duty is distributed automatically due to the evaporation of the cooling agent in the auxiliary agent. Considering, for example, the auxiliary agent as hydrogen, the ability of ammonia to evaporate into hydrogen varies with different temperatures, increasing as the temperature rises. Thus, as one evaporator is given a. greater load than another, the temperature of the auxiliary agent rises,'and, as it rises more of the cooling agent evaporates into the auxilliary agent so that a greater refrigeration is produced. Thus a balance is obtained between a plurality of evaporators whereby high efficiency of distribution is obtained by the automatic operation of internal fluids of istics.

Another object of the present invention is the utilization of excess liquid refrigerant which would not otherwise evaporate. Still from the following description takenin con-y nection with the accompanying drawings on which Fig. 1 shows more or less diagrammatically the system due to internal physical characteran absorption system in which one form of the invention is embodied;

Fig. 2 shows another application of the invention wherein a different arrangement part of the apparat-us shown in Fig. 3;

Fig. 5 shows a surface contact disk used' in the absorption system; and i Fig. 6 shows still another applicationl of the invention wherein two evaporators are used for cooling Idifferent external objects.

Referring more particularly to Fig. 1, reference character 1 designates a generator .wherein is contained the refrigerant or cooling agent in solution in an absorbing liquid. For convenience in reference let it be assumed that the 4refrigerant is ammonia and the absorption liquid is water. Generator 1 is heated in any convenient way, as for instance,- by the electrical resistance coil 9. The heat thus applied to the generator and its con.l tents drives the ammonia out of solution. The gaseous ammonia passes upwardly through conduit 10 to'the air-cooled rectifier or radiator 2 where any entrained water vapor iscondensed and flows by gravity back to the generator. The ammonia vapor free from water passes into condenser 3 where it is cooledby cooling water -or other means and is liquefied. The liquid ammonia flows downwardly through condenser 3 to the upper part of the primary evaporator l which is the regular or ordinary evaporator of the type of system dealtl with in Patent .No.

l1,609,334 of .December 7,1926. An auxiliary agent, a gas inert with respect -to ammonia, for instance hydrogen, also enters the top of the evaporator 4 through conduit 17. The

invention wherein further heat exchange l ammonia diffuses into the hydrogen, producing refrigeration. Diffusion and evaporation in the evaporator are aided by disks 36 v 'y placed4 therein. v

The mixture of ammonia and hydrogen formed in the evaporator has a greater specific weight than the relatively pure hydro- Cal gen which enters tlie evaporator' at tlief-top` gaseous ammonia and hydrogen and excess liquid ammonia that has not evaporated passes downwardly through the evaporator 4 and through conduit 37 to a vessel 5 situated below primary evaporator 4which will hereinatter be referred to as the secondary evaporator. lVithin the secondary evaporator 5 is a series ot' disks 39 which aid in the .coniplete evaporation of the liquid ammonia which enters the vessel. This evaporation absorbs heat from hydrogen in vessel l4as will be explained more fully later.

The gaseous mixture of ammonial and hydrogen passes out from the bottoni of the secondary evaporator 5 through conduit 15 to the lower part ot absorber 6. Absorption liquid which contains but little ammonia in solution enters the top ot the absorber 6 through conduit 11 and falls down over disks 40 placed within the absorber and comes in contact with the ammonia-hydrogen mixture. The ammonia is absorbed by the absorption liquid and the hydrogen iemains. This Comparatively pure hydrogen is lighter than the ammonia-hydrogen mixture and passes upwardly through the absorber and through conduit 16 to the bottoin of cooling vessel 14 and thence through conduit 17 to the top of the primary evaporator. Members 4, 37, 5,

15, 6, 16, 14 and 17 forni a local cycle ofy circulation for hydrogen of which there is a down-leg iii the evaporators and conduit 37 and an lip-leg in the absorber and coni' uit 17, the heavier specific gravity ot' fluids in the down-leg serving to cause continuous circulation iii the local cycle. Vessel 14'is arranged in heat exchange relation with the seeondary evaporator 5 and the hydrogen in cooling vessel 14 is cooled by evaporation of ammonia in the secondary evaporator as it diffuses into hydrogen therein. Fins 13 are supplied on the secondary evaporator 5 to increase the rate of heat transfer from the hydrogen. In order to prevent accumulation et water in vessel 14 which may be entrained with hydrogen passing through conduit 16, a small drain conduit 42 is connected between vessel 14 and conduit 15. Water condensate in vessel 14 flows through eonduits42 and'lv into the absorber. l Y

The absorption liquid which contains aninionia in solution passes out of the bottom of absorber 6 through conduit l12, a portion ot which is arranged as a coil 8 around the heat-1 `ing element 9 so as to form a thermo-siplion.

This thermo-Siphon causes the liquid to How' upwardly through conduit 12 from which-it is discharged into the upper part ot thel genicrator 1 at a level otliqiiid above that niaintained in the absorber. In the generator the ously described and thus completes its cycle. The absorption liquid Hows downwardlyflows through conduit 20 to tlieftop of" Y oiidaiyeva]iorator 5where itji'niis'f the li( annnoiiia which is'here introduced through` conduit Secondary. evaporator 5 fisso through the generator and throughcoii d uit 11 through conduit 17. Hence the mixture of to tlle'topot1 the absorber andthus itscycle is completed. This fion/of the absorption liquid takes` place because the therino-si phon nienjiberSmaintains ka level-oit liquid in the generator above tlielpoiiit of discharge from -conduit 11 into the vabsorber 6. Conduits 11 and 112 maybe arranged in limit-exchange rclatioii as indicated at 7 so that the hot liquid which comes from the generator will bc cooled be t'ore it enters the absorber while at the saine time the relatively cold liquid which coiucs from the absorber is heated before it enters the thermo-siphon. absorber and condenser is supplied through conduit 50, passes through jacket 51. thence through conduit 52, through jacket 53 ot the condenser and out through conduit`54.

Cooling water for the lt will be not-ed that it is the latent heatof vaporization of the ammonia which cools` the hydrogen in vessel 14-rather than merely the heat ot' superheat which was previously used for this purpose as disclosed in the patent above referred to. By using the latent heat ot' .vaporizatiom a greater cooling efectcan lbe obtained than with merely transfer of the heat of gas. l

Considering the members 4 and 5 as one combined unit, it inightbe said that the hydrogen passes in heat'exchange relation with a p. `tion ot' the outletend of the' evaporator before entering the evaporator. Conduit'37 constitutes a colder portion ot the evaporator as a whole than the actual outlet end.

The cycles of operation of the apparatus shown in Fig. 2 are, in general, similar.l to those described above.'l Gaseous ammonia passes from the generator 1 through conduit 10 and rectifier 2 into l,condenser 3. The liquid ammonia which leaves the condenser divides'. however, and a small proportionV thereofl Y flows through a narrow 'conduit'23 directly to" secondary evaporator 5 while tliefreinainder -l ne Fig. 1. The ammonia-hydrogen mixture and any liquid ammonia that has not evapo- 1 rated'in its passagethrougli theevapo jator"AV fl constructed and a rrangedv as tOEsurrou'ud th upper part ot absorber 6 andthe lower 'por 512e tion ot' conduit 2l `wli'icliconducts"hydrogen lfroinfthe upper parteiV the absorber to the upper part of theevaporator. TSe'condary" ,evaporator 5 is provided ywith a'seriesfot; .battle plates ordisks39. The liquid ammonia which enters secolidarywevaporator 5 throi'igli .K `conduits 23 and 20 .diffuses vinto and evapo ammonia. is driven out of solution as previrates-iii the presence otthe khydrogen iii-a l in, @Imation WithiFg? '111.-

.which leaves the absorber.

In Fig. 2, it will be seen that evaporation serves to cool the absorption liquid which e11- te-rs the'absorber as well as the hydrogen This is accomplished partly by arranging conduit 11 to pass partly through secondary evaporator 5 and Ypartly by transfer of heat from absorption liquid on the upper disks in .the evaporator to the fluid within the secondary evaporator. 'lhrce fluids are here in heat exchange relation: (l) the mixture of ammonia' and hydrogen; (2) liberated hydrogen; and (3) absorption liquid.

The ammonia-hydrogen mixture passes from secondary evaporator 5 through conduit 22 vto absorber 6 where the ammonia is alosorbed by the absorption liquid which has been cooled by the secondary evaporator'. The hydrogenpasses upwardly through the absorber and conduit 21 to -the evaporator. The absorption liquid which contains ammonia in solution flows from absorber 6 throughconduit 12 to generator 1 in the same manner as was described in reference to Likewise, in the apparatus shown in Fig. 3 the cycles of operation are substantially those described in relation to Fig. 1. Gaseous ammonia passes from generator 1 through conduit 10 and rectifier 2 to condenser 3. Liquid ammonia passes through conduit 24 to evap- `orator 4 where evaporation takes place in the presence of hydrogen as has been previously described. The mlxture of gaseous ammonia and hydrogen together with llquld ammoma v that has not evaporated leaves the bottom of the evaporator throughconduit 34. A short distance from the evaporator, conduit 34 makes asharp upward bend. Communicating with conduit 34 at this bend is conduit 3l through which the liquid and a portion of the gaseous ammonia-hydrogen mixture/ flows' to the top of secondary evaporator 5. The remainder of the gaseous ammonia-hydrogen mixture passes upwardly through conduit 34 to the Aheat exchanger 18 wherein it flows downwardly through tubes extending between tube heads 56 and absorbs heat from the hydrogen which asses; upwardly through space 57 surrounding tubes 55. The mixture leaves the heat exchanger through conduit 35 and enters the absorber 6 where the ammonia is absorbed. A small drain hole 58 is provided in lower tube head 56.

- The mixture of gaseous ammonia and hy-' drogen and liquid ammonia which passes through conduit 3l enters secondary evaporator 5 where the liquid ammonia evaporatcs and absorbs heat. One form of secondary evaporator which may be used is shown more in detail in Fig. 4. It has the form of. a hollow cylinder on the inside of which is formed a spiral groove 80. The cylinder lits snugly over and is welded to conduit 30 and thus a spiral path is provided in which the ammon1a evaporatcs in the presence of hydrogen. The gaseous ammonia-hydrogen mixture passes through conduit 32 to conduit 35 through which it passes to the absorber.

The hydrogen, freed from its mixture with ammonia in the absorber, passes upwardly through the absorber to conduit 30. A portion of conduit 30 is .within secondary evaporator 5 as described above and in this portion of the conduit the hydrogen is cooled by the evaporation ofthe ammonia in the secondary evaporator. The hydrogen is further cooled during its passage through heat exchanger 18. From heat exchanger-18 the hydrogen is int-roduced to the top'of evaporator 4 through conduit 33. v y

The cycle of the absorption liquid between the absorber and generator takes place in the same manner as described in reference to Fig. l and Fig. 2.

Fig. 5 shows a preferred form of disk for apparatus hereinbefore described. The disk, which may be considered as disk 36 of Fig. l, contains two passages, one for gas 60 and one for liquid 61. A lou7 rim 62 surrounds passage 60 to allow a pool of liquid to accumulate and a higher rim 63 surrounds passage 60 to prevent liquid from flowing through the gas passage.

In F ig..6 is shown a refrigerating apparatus wherein a primaryv and a secondary ments of a refrigerating cabinet.. Reference .character 75' designates a compartment particularly intended for makingice. Reference character 76 represents a compartment for cooling food and the like. The two compartments are separated by means of insulating material 78 and have separate doors for access thereto respectively. Primary evaporator 84 in compartment 75 is similar to evaporator 4 of the previous modifications. Secondary evaporator 85 in compartment 76 is similar to evaporator 5 of the previous embodiments. In this case, the primary evaporator is smaller than the secondary evaporator in order to obtain a proper proportion of surfaces of the evaporators for freezing ice and preserving food respectively. Surrounding the primary4 evapo- 'rater is a casting 70 which may be made of alumnium or likemetal which m-ay be bound to, orv welded to, or soldered to, the evaporator in any suitable way. Casting 70 has a than preserving food. If all the liquefied refrigerant were evaporated at the lower tempera'ture necessary for the product-ion of ice,

the ellicicncy ol the apparatus would be lower 'than il' some of the liquefied refrigerantfis evaporated at higher temperature adequate for preserving food. In the arrangement yherein described, only that part of the lique-' fied refrigerant necessary for the production of ice is evaporated at the low partial pressure causing this low tempeiature, While the part utilized for preserving food is evaporated at a higher partial pressure and i f higher temperature which makes it possible orators is of relatively small size in order to minimize heat'ti'ansier from the secondary vvevaporator to the primary evaporator.

, Bygmeans of this arrangement in a system ,Y y employing an auxiliary pressure equalizing medium, the refrigerative load is distributed autoir'iaticvally between the evaporators due to 'the' internal characteristics of the uids with-v out-using'automatic valves or the like. To

illustrate, suppose that the primary. evaporator contains ammonia and hydrogen. Suppose that the trays 72 contain water.. When.

sufficient heat has been abstracted to completely freeze the water in trays 72, the temperature drops and as it drops the ammonia is less able to evaporate into the'liydrogen. The temperature drops to a point where ractically no further evaporation of the refrigerant will occur. At a temperature of minus 30 centigrade practically no evaporation is obtained. Therefore, -substantially all the liquid refrigerant flows into the secondary evaporator and diusesinto hydrogen in the secondary evaporator, at which time the primary evaporator is automatically put out of service due to its low temperature. Heat introduced into eithercompartment, by opening the different doors of the two compartments, will be automatically and'individually absorbed since an increase of temperature of either evaporator causes a greater amount of the refrigerant to evaporate quickly in the respective evaporatoi's.

While we have described several forms of our invention, it is to be understood that we are not limited to the Structures shown and described but that the invention is to be gaged by the scope of the prior art taken in connect-ion with the appended claims.

Having thus described our invention, what we claim is:

1. Refrigerating apparatus of the absorption type coii'iprising a generator, a condenser, a primary evaporator, a secondary I evaporator, an absorber, said primary evaporator being positioned above said secondary evaporator, the evaporators being connected in series, means to conduct vapor of a'cooling agent from the generator'tothe condenser, means toconduct liquid cooling agent from the condenser to the primary evap orator, means to conduct anauxiliary agent in the presence of which the cooling agent evaporates from the absorber to the primary evaporator, means to conduct gaseous fluid fromvthe secondary evaporator to the absorber whereby some of the cooling agent difuses into the auxiliary' agent iny the primary evaporatorat a relatively low temperature and some of the cooling agent diffuses into the auxiliary agent in the secondary evaporator at a relatively high temperature andmeans to circulate absorption liquid between tlie generator andabsorber.

2. Refrigerating apparatus comprisinga primary. evaporator, conduits forming a cycleA of circulation for an auxiliary agent in the presence of which the cooling agent evap` crates through the absorber, the primary evaporator, the secondary evaporator and back' to the absorber, .one of said conduits being adapted to conduct liquid refrigerant `from the primary evaporator to the secondary evaporator and means for circulating absorption liquid between the generator and absorber.. v

e 3. Absorptionl refrigerating apparatus of the type wherein a pressure equalizing medium is employed comprising a primary evaporator, a series ofdisks within said evaporator, a secondary evaporator situated below said primary evaporator, a series of disks in said secondary evaporator and means -forming a restricted communication between the primary evaporator and the secondary evaporai tor.

4. Absorption refrigerating apparatus of the type whereiny a pressure equalizing niedium 1s employed comprising a primary evaporator, a series of disks within said evaporator for distributing liquid, a second ary evapoiator situated below said primary evaporator, a series of disks in said secondary eva porator for distributing liquid. means forming a restricted communication between the primary evaporator and the secondary evaporator, an absorber, a conduit connecting said secondary evaporator with said absorber, a conduit connecting said absorber with said primary evaporator, a generator, means for circulating absorption liquid between said generator and said absorber and means to receive vaporous refrigerant from the generator, liquefy the same and conduct the liquid refrigerant to the primary evaporator.

5. Absorption refrigerating apparatus of the type wherein a pressure equa izing medium is eniployed comprising a primary evaporator, a series of disks within said evaporator, a member surrounding said primary evaporator adapted to contain icc trays, a secondary evaporator situated below said primary evaporator, a series of disks in said secondary evaporator, means forming a restricted communication between the primary evaporator and the secondary evaporator, means -for transmitting heat from surrounding atmosphere .to said secondary evaporator, an absorber, means to conduct fluid from the lower part of said secondary evaporator to said A absorber, means to conduct fluid from the up- Vper part of said absorber to said vprimary evaporator, a generator, means to circulate absorption liquid between the generator and the absorber, condenser, means to conduct vaporous refrigerant from the generator to the condenser and means to conduct liquid refrigerant from the condenser to the primary evaporator.

6. That improvement in the art of refrigerating through the agency of a System employing an auxiliary agent in the presencel of which the cooling agent evaporates which consists in successively diffusing a portion of the cooling agent into the auxiliary agent in heat exchange relation-with water to be converted into ice and the remainder of the cooling agent into the auxiliary agent at a higher temperature in heat exchange relation with surrounding, atmosphere and isolating the portions diii'using at different temperatures.

7. That improvement in the art of refrigerating through the agency of a system employing. an auxiliary agent in the presence of which the cooling agent evaporates which consists in successivelydiifusing a portion of the cooling agent into the auxiliary agent in heat exchange relation with water to be converted into ice and the remainder of the cooling agent into the auxiliary agent at a higher temperature in heat exchange relation with surrounding atmosphere and isolating the ortions diiusing at different temperatures Vy restricting flow of fluid between the space of low temperature dii'usion and the spacei of high temperature diffusion.

8. That improvement in the art of refrigerating through the agency of a system employing an auxiliary agent in the presence of which the cooling agent evaporates which consists in successively diffusing portions of the cooling agent into the auxiliary agent in a kplurality of substantiallyisolated spaces at different temperatures and varying the rate of diili'usion in the spaces in accor ance with variations in temperature of the auxiliary agent.

9. A refrigerator comprising a plurality of compartments, heat insulating material separating the compartments, a primary evaporator situated in one compartment, a secondary evaporator situated in another compartment, .said primary evaporator being smaller thansaid secondary evaporator, ico forming means in heat exchange relation with the primary evaporator, the compartment containing the second evaporator being adapted to contain food, a conduit connecting the primary evaporator with the secondary evaporator passing through the heat insulating material, an absorber, a generator, a condenser, means to conduct vaporous cooling agent from the generator to the 'condenser, means to cond-uct liquid cooling agent from the condenser to the primary evaporator, means to circulate an auxiliary agent, in the presence of which the cooling agent evaporates, through the evaporators in series and through the absorber and means to circulate absorption liquid between the generator and absorber. v

10. A refrigerator' comprising a plurality '90 of compartments, heat insulating material separating the compartments, a primary evaporator situated in one compartment, a secondary evaporator situated in another compartment, a conduit connecting the primary evaporator4 with the secondary evaporator passing through the heat insulating material, an absorber, a generator, a condenser,` means to conduct vaporous cooling agent from the generatorio the condenser, 100 means to conduct cooling agent from the condenser to the primary evaporator, means to circulate an auxiliary agent, in the presence of which the cooling agent evaporates, through the evaporators in series and through 105 the absorber and means to circulate absorp- 'tion liquid between the generator and absorber. v

11. A refrigerator comprising a plurality of compartments each having'l separate doors, '110 heat insulating material separating the compartments, a primary evaporator Ysituated in one compartment, a secondary evaporator situated inanother compartment, a series of" disks in each of such evaporators for distributing liquid'within the same, said primary evaporator being smaller than said sec ondary evaporator, ice forming means in heat exchange relation 'with the primary evaporator, the compartment containing the secondary evaporator being adapted to contain food, means for transferring heat from surrounding latmosphere tothe secondary evaporator within the food compartment, a conduit connecting the primary evaporator with the secondary evaporator pasing through the heat insulating material, said primary evaporator being positioned above said secondary evaporator and the connecting'conduit being adapted to permit flow by gravity of liquid therethrough,agenerator,acondenser, sorber and means vto circulate absorption' means 'tobonducbv'aporous cooling agent liquid between the generator and absorber. 1oVv from the generator tothefcondenser, means In testimony whereof we have hei'eunto af- 1 to conduct cooling 'agenti-om the condenser `fixed. Our Slgnatures. to the primary evapolator,-means to clrculate au auxiliary ga`S`,--invthe.presence of which BALTZR CARL vVON PLATEN- the coolingfagent;evapopltes,v throu 11 the CARL GEORG MUNTERS. 4 v

vjevaporatorsjinI.series vand". through tle ab- SIGURD MATTIAS B2SCKSTRM. 

